Posttraumatic stress symptom clusters associations ...

Journal of Anxiety Disorders 24 (2010) 936–940

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Journal of Anxiety Disorders

Posttraumatic stress symptom clusters associations with psychopathology and functional impairment Trond Heir ∗ , Auran Piatigorsky, Lars Weisæth Norwegian Centre for Violence and Traumatic Stress Studies, University of Oslo, Norway

a r t i c l e

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Article history: Received 5 February 2010 Received in revised form 18 June 2010 Accepted 19 June 2010 Keywords: Natural disasters Post-traumatic stress PTSD criteria PTSD conceptualization

a b s t r a c t We examined posttraumatic stress symptom clusters associations with psychopathology and functional impairment in 899 Norwegian survivors of the 2004 South-East Asia tsunami six months post-disaster. Posttraumatic stress symptoms were assessed with the Impact of Event Scale-Revised (IES-R) with intrusion, avoidance, and hyper-arousal subscales. For criterion variables, we used 10 indicators of psychopathology and functional impairment, e.g. having mental health problems, seeing mental health professionals, and use of medication or sick leave. Hyper-arousal had stronger correlations than avoidance with all criterion variables (p values < 0.001) and stronger correlations than intrusion with seven of the 10 criterion variables (p values < 0.01). Also, intrusion had stronger correlations than avoidance with seven of 10 criterion variables (p values < 0.05). Thus, our findings indicate that symptoms of hyperarousal may be more closely linked to psychopathology and functional impairment than other symptoms of posttraumatic stress following a sudden onset, short duration, natural disaster event. © 2010 Elsevier Ltd. All rights reserved.

1. Introduction Fueled by the pending publication of the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (DSM-V, http://www.dsm5.org/), there is considerable controversy about how to define the diagnostic criteria of posttraumatic stress disorder (PTSD). Presently, the DSM-IV-TR organizes PTSD symptoms into three clusters: intrusion, avoidance/numbing, and hyperarousal. Criteria for PTSD require ≥one of five intrusion symptoms (Criterion B), ≥three of seven avoidance/numbing symptoms (Criterion C), and ≥two of five hyper-arousal symptoms (Criterion D). Yet it remains unclear whether these relative contributions of symptoms to the PTSD diagnosis accurately reflects the core features of traumatic stress (Ehlers, Mayou, & Bryant, 1998; Maes et al., 1998; North, Suris, Davis, & Smith, 2009; Rosen & Lilienfeld, 2008; Spitzer, First, & Wakefield, 2007). Following a trauma, individuals cross the diagnostic threshold for PTSD Criterion C less often than they cross the thresholds for Criteria B and D (Catapano et al., 2001; Ehlers et al., 1998; Maes et al., 1998; McMillen, North, & Smith, 2000; North et al., 1999; North et al., 2005). This has led several authors to assert that the avoidance/numbing symptom cluster drives the diagnosis of PTSD (Breslau, 2001; Norris et al., 2002; North et al., 2009). The relatively

∗ Corresponding author at: Norwegian Centre for Violence and Traumatic Stress Studies, Building 48, Kirkeveien 166, N-0407 Oslo, Norway. E-mail address: [email protected] (T. Heir). 0887-6185/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.janxdis.2010.06.020

crucial importance of Criterion C may be due to at least two reasons, Criterion C symptoms being less prevalent than Criteria B and D symptoms in traumatized populations (Ehlers et al., 1998; Foa, Riggs, & Gershuny, 1995; North et al., 1999; Solomon & Canino, 1990), and\or it may be due to the higher number of Criterion C symptoms required. Thus, the findings that Criterion C predicts PTSD (Maes et al., 1998; North et al., 1999; North et al., 2005) as well as the conclusion that “group C is a marker for PTSD” (North et al., 2009, p. 38) may be a consequence of the current conceptualization of PTSD rather than the importance of the avoidance/numbing symptoms themselves. This debate calls for empirical investigations of which symptoms are linked to psychopathology and functional impairment (North et al., 2009). Surprisingly, few studies have explored these associations. In their study of Oklahoma City bombing survivors, North et al. (1999) found that surpassing the Criterion C threshold was associated with difficulties in functioning and treatment received. In the absence of Criterion C symptoms, however, surpassing Criterion B or D thresholds was not associated with psychopathology or functional impairment. In contrast, Ehlers et al. (1998) observed that among motor vehicle accident patients, “a substantial proportion of those who did not meet the avoidance criterion reported disability. These patients may require treatment, and it may not be sensible to assign them non-patient status just because they do not meet an arbitrary score for avoidance and numbing criteria” (p. 516). Our sample of Norwegian tourists who were repatriated from South-East Asia shortly after the 2004 tsunami offers a unique

T. Heir et al. / Journal of Anxiety Disorders 24 (2010) 936–940

opportunity to study the relative burden of posttraumatic symptoms in a community sample exposed to a well-defined, sudden onset, short duration event. Geographic differences in disaster severity resulted in a wide range of exposure and of posttraumatic stress reactions accordingly (Heir et al., 2010; Heir & Weisæth, 2008; Kraemer, Wittmann, Jenewein, & Schnyder, 2009). Previous analyses showed that symptoms of hyper-arousal were more closely linked to disaster exposure than other symptoms of posttraumatic stress (Heir, Sandvik, & Weisæth, 2009). Our present study expands on this previous finding by investigating the relationship between PTSD symptom clusters and psychopathology and associated functional impairment. 2. Method 2.1. Participants Our study population consisted of Norwegian nationals over the age of 18 years who had been in disaster-stricken areas during the 2004 tsunami. A total of 2468 Norwegian nationals was eligible for our study. Of these, 899 individuals (36%) returned our questionnaire. From this sample, 55 respondents were excluded due to missing data. Compared to the 1624 individuals who were excluded, the remaining 844 participants – our final sample – had similar age to the excluded individuals (mean 43.4 years), and a higher proportion of women (53%) (Heir et al., 2009). Nonresponders were less likely to have been exposed to the tsunami than responders, and they had lower levels of posttraumatic stress symptoms (Hussain, Weisæth, & Heir, 2009). In the final sample, 60% of the participants had more than 12 years of education, 74% were employed, and 66% were married or cohabitating with their partner. Also, 66% of participants were travelling with their spouse or live-in partner, 37% with their children under 18 years of age, and 14% with their parents. Prevalence of contact with a general medical practitioner, psychologist, or psychiatrist for mental health problems prior to the tsunami was 22%. The participants were similar to the age and sex adjusted Norwegian population with regard to employment and marital status (Statistics Norway, http://www.ssb.no/english/). 2.2. Measures We sent a questionnaire to subjects’ home addresses six months after the disaster. The questionnaire queried demographic variables, their exposure to the tsunami, current symptoms of posttraumatic stress, and indicators of psychopathology and functional impairment. The questionnaire asked about specific details as for disaster exposure, allowing us to classify participants into three groups of exposure severity (for details, see Heir et al., 2009). The danger exposed group consisted of individuals that had life-threatening exposure to the tsunami (e.g., being caught by the wave), the nondanger exposed group included individuals that experienced the tsunami without any immediate life threat (e.g., witnessing others’ deaths or suffering), and the non-exposed reference group consisted of individuals who were present in South-East Asia, but with limited exposure to the tsunami. We used the Impact of Event Scale-Revised (IES-R) (Weiss & Marmar, 1997) to examine the presence and intensity of PTSD symptoms during the previous week. Participants responded to each item on a five-point Likert scale that ranged from 0 (not at all) to 4 (extremely) with regard to their tsunami experience. We used IES-R mean subscale scores of intrusion, avoidance/numbing, and hyper-arousal as semi-continuous measures of PTSD symptom severity.

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We queried multiple variables of psychopathology and functional impairment. Participants were asked whether they had subjective mental health problems that they attributed to the tsunami (scored from (0) ‘not at all’ to (3) ‘yes, definitely’), saw a physician (dichotomized), were referred to psychologist or psychiatrist (dichotomized), used sick leave or disability (number of days absent during last month, grouped into 0, 1–13, and 14+), and used psychotropic medication (scored from (0) ‘no’ to (3) ‘every day’). Furthermore, we included the General Health Questionnaire (GHQ28) (Goldberg & Hillier, 1979) as a measure of general psychological distress during the previous week (Likert scale, scored 0–1–2–3). Also, with the Post-Traumatic Symptom Scale (PTSS-10, scored from (0) ‘never’ to (6) ‘very often’) (Holen, Sund, & Weisæth, 1983), we used items to assess sleep disturbance, social withdrawal, and guilt. Finally, we used the Cantril’s Ladder of Life Satisfaction (CLLS) (Cantril, 1965) to measure current life satisfaction (scored from (1) ‘worst possible life’ to (10) ‘best possible life’ imagined). 2.3. Procedure Norwegian police registered names, personal identification numbers, and places of residence in South-East Asia during the disaster. With permission from the Norwegian Data Inspectorate and the Regional Committee for Medical Research Ethics, this information was made available for our study. One additional request for participation was mailed to non-participants. For each participant, a missing item response on a psychometric instrument was replaced with the item score on the same instrument that, on the sample level, had the highest correlation coefficient (kappa value) with the missing item. We excluded participants from analyses if their responses had ≥30% missing data within a measure or subscale. 2.4. Analysis of data We performed chi-square tests or one-way ANOVAs (Kruskal–Wallis) to compare the three allocated exposure groups with regard to PTSD symptom clusters, psychopathology and functional impairment. We used Spearman rho to test correlations between PTSD symptom clusters and indicators of psychopathology and functional impairment. Differences between pairwise PTSD symptom cluster scores were found to be normally distributed, and thus we examined differences between paired correlations with t-tests of two dependent correlations from the same sample (Chen & Popovich, 2002). With x and z denoting the scores of two selected symptom clusters, and y denoting the indicator of psychopathology or functional impairment, the significance of the difference of x’s and z’s correlation with the indicator y was calculated with the following formula: t = (rxy − rzy ) ∗ SQRT (((n − 3)(1 + rxz ))/ 2 2 2 − rxz − rzy + 2rxy ∗ rxz ∗ rzy ))) (2(1 − rxy

where r is the absolute value of a correlation coefficient and n is the sample size. All tests were two-tailed and differences were considered significant if p < 0.05. We performed statistical analyses with the software package SPSS, version 16.0. 3. Results Table 1 presents IES-R subscales and other indicators of psychopathology and functional impairment in two groups of exposed participants and a non-exposed reference group. Significant outcome differences were found between the groups, regardless of which of the indicators were applied. In general, the more the exposure, the more psychopathology or functional impairment. The

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Table 1 Post-traumatic stress, psychopathology and functional impairment in 2 exposure groups and a reference group of tourists who were in the area at the time of the disaster* .

Intrusion Avoidance Arousal

Not directly exposed (n = 124)

Non-danger exposed (n = 434)

Danger exposed (n = 286)

Mean

SD

Mean

SD

Mean

SD

0.49 0.45 0.20

0.60 0.54 0.36

1.34 0.96 0.87

0.96 0.82 0.88

1.84 1.18 1.36

0.93 0.79 1.04

N

%

N

%

N

%

92.7 1.6 2.4 0.0

258 88 62 23

59.4 20.3 14.3 5.3

131 51 50 51

45.8 17.8 17.5 17.8

89.5 10.5

268 166

61.8 38.2

136 150

47.6 52.4

100.0 0.0

409 25

94.2 5.8

239 47

83.6 16.4

Use of psychotropic medication last month No 80 Few times 26 Every week 2 Every day 3

64.4 21.0 1.6 2.4

167 173 36 36

38.5 39.9 8.3 8.3

123 93 30 32

43.0 32.5 10.8 11.2

Sick leave (number of days during last month) 0 94 1–13 15 14+ 7

81.0 12.9 6.0

304 57 54

73.3 13.7 13.0

193 28 46

72.3 10.5 17.2

Mental health problem attributed to the tsunami Not at all 115 Probably not 2 Probably yes 3 Yes, definitely 0 Seeing a physician for mental health problem No 111 Yes 13 Referral to psychologist or psychiatrist No 124 Yes 0

General mental health distress Sleep disturbances Social withdrawal Feelings of guilt Life satisfaction

Mean

SD

Mean

SD

Mean

SD

0.70 1.92 0.55 0.42 7.80

0.35 1.46 1.25 1.05 1.79

0.92 2.96 1.26 1.11 7.28

0.48 2.00 1.75 1.59 1.77

1.07 3.34 1.75 1.50 6.90

0.55 2.17 1.97 1.73 2.12

* All comparisons between the allocated groups (Chi-square or Kruskal–Wallis tests) are significant at the p < 0.001 level, except the comparison of sick leave which is significant at the p < 0.05 level.

allocated groups did not significantly differ in gender, age, education, employment, family constellations, or predisaster contact with mental health professionals. IES-R subscales significantly correlated with all other indicators of psychopathology and functional impairment (Table 2). Most correlations were small or moderate. Hyper-arousal correlated more strongly with all criterion variables than the other symptom clusters, especially avoidance (Table 3). Also, hyper-arousal significantly correlated more than intrusion with seven of 10 indicators of psychopathology or impairment: subjective health problems that were attributed to the tsunami, sick leave last month, general mental health distress (GHQ-28), sleep disturbance, social withdrawal, feelings of guilt, and life satisfaction. Furthermore, intrusion correlated more than avoidance with seven of 10 criterion variables: subjective health problems that were attributed to the tsunami, seeing a physician, referral to psychologist or psychiatrist, use of psychotropic medication, general mental health distress (GHQ-28), sleep disturbance, and feelings of guilt (Table 3). 4. Discussion In our Norwegian community sample, the PTSD hyper-arousal symptom cluster, compared to the other PTSD symptom clusters, was most closely linked to indicators of psychopathology and functional impairment six months after exposure to the 2004 South-East Asian tsunami. Of note, the avoidance symptom cluster had the smallest magnitude of correlations with psychopathology and functional impairment.

Our results directly contradict some other findings. For example, after the Oklahoma City bombing, study participants that surpassed the Criterion C threshold also had significant associations with several indicators of impairment, while participants that surpassed the intrusion and hyper-arousal symptom cluster thresholds, in the absence of meeting the arousal/numbing threshold, did not have significant associations with impairment (North et al., 1999). Another study with a community sample partly underscored this pattern of findings (Breslau, Reboussin, Anthony, & Storr, 2005). However, the relative contribution of avoidance/numbing symptoms to impairment may be overstated. Regardless of the type of symptoms experienced, simply meeting a more stringent three-symptom threshold (i.e., Criterion C), rather than a two or one symptom threshold (i.e., Criteria B and D), may account for significant associations between avoidance/numbing symptoms and impairment. If so, the relative importance of the avoidance/numbing symptom cluster may be an artefact of the DSM-IV conceptualization of PTSD rather than the nature of the symptoms themselves. In our study, we used dimensional variables of PTSD symptom counts rather than categorical variables of surpassing symptom cluster thresholds, with the aim of side-stepping the above mentioned artefact. Importantly, hyper-arousal symptoms were more strongly associated with psychopathology and functional impairment than other PTSD symptoms. Our previously published results indicated that hyper-arousal was more closely linked to the degree of exposure than other symptom clusters, albeit it was not the most commonly experienced symptoms (Heir et al., 2009). Indeed,


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Table 2 Correlations between PTSD symptom cluster levels and indicators of psychopathology or functional impairment* . Intrusion

Mental health problem attributed to the tsunami Seeing a physician Referral to psychologist or psychiatrist Use of psychotropic medication Sick leave last month General mental health distress (GHQ-28) Sleep disturbances Social withdrawal Feelings of guilt Life satisfaction *

Avoidance

Hyper-arousal

Spearman rho

95% confidence interval

Spearman rho


Spearman rho


.59 .39 .25 .35 .21 .58 .57 .51 .52 −.32

.55 to .64 .33 to .44 .18 to .31 .29 to .41 .15 to .28 .53 to .62 .53 to .62 .45 to .56 .47 to .57 −.38 to −.26

.51 .33 .16 .26 .18 .50 .42 .48 .43 −.29

.46 to .56 .27 to .39 .09 to .23 .19 to .32 .11 to .25 .45 to .55 .36 to .47 .43 to .53 .37 to .48 −.35 to −.23

.68 .42 .28 .36 .28 .69 .61 .61 .58 −.43

.64 to .71 .37 to 48 .21 to .34 .30 to .42 .21 to .34 .65 to .72 .56 to .65 .57 to .65 .54 to .63 −.48 to −.37

All correlations are significant (p < 0.001).

increased arousal appears to reflect crucial features of the stress response to a sudden onset, short duration, natural disaster event, and in our sample, the more the arousal, the more the impairment. The conceptualization of posttraumatic stress may depend on the nature of the stressor. For example, Naifeh, Elhai, Kashdan, and Grubaugh (2008) proposed that PTSD that results from a specific trauma exposure may yield a factor structure that is more consistent with the arousal component of anxiety disorders, as opposed to exposure to non-specific stressors, which may yield a factor structure that is more consistent with the underlying negative affect of depressive disorders. Due to immediate repatriation, our sample did not experience secondary disaster stressors, such as destroyed communities, loss of property and livelihood, and uncertainty about the future. For these reasons, possibly, we found a relatively prominent hyper-arousal response and a relatively small depressive response in our tourist sample (Heir et al., 2009) compared to samples of native tsunami survivors (Hollifield et al., 2008; Kumar et al., 2007; van Griensven et al., 2006). Thus, the relative contribution of PTSD symptom clusters to psychopathology and functional impairment may depend on the nature of the traumatic event, accordingly. 4.1. Methodological considerations We included a wide range of indicators of psychopathology and functional impairment, which yielded consistent findings. In the absence of a comprehensive psychiatric examination, we refrained from estimating the diagnostic prevalence of PTSD. Therefore, analyses herein are restricted to symptom dimensions measured by psychometric scales. Symptom dimensions are useful because they are less bound by current diagnostic conceptualizations of posttraumatic stress. After all, research suggests that PTSD is better

conceptualized as the upper end of the stress response continuum, rather than a qualitatively distinct category (Broman-Fulks et al., 2006; Forbes, Haslam, Williams, & Creamer, 2005; Palm, Strong, & MacPherson, 2009). Thus, our results examine impairment in the context of symptom counts rather than meeting pre-conceptualized diagnostic cut-offs for PTSD. Our study has a number of methodological benefits. Virtually the entire population of Norwegians who were in South-East Asia during the 2004 tsunami was asked to participate in our study, reducing sample-selection bias. Unlike other studies, our sample was exposed to a single, discrete event, and then participants were quickly removed to their unaffected home communities in Norway. Thus, our study isolates the impact of acute exposure to a natural disaster without the disruption of normal life that typically follows natural disasters (i.e., secondary stressors). Findings herein may not be relevant to populations that are exposed to other types of severe stressors. Accordingly, our hypotheses should be examined further in other relevant databases. Limitations of our study include a relatively low response rate, which suggests a self-selection bias. However, women and men in all age groups were represented, participants and non-participants were similar with regard to age, and participants were similar to the general Norwegian population with regard to employment and marital status. Our findings are also limited by self-report and our reliance on a single instrument to assess PTSD symptoms. 4.2. Implications Our previous results, which showed that hyper-arousal was more closely linked to acute tsunami exposure (Heir et al., 2009), in concert with our present results, which indicate that hyperarousal was more closely linked than other symptoms of PTSD to

Table 3 Significance of differences between pairwise correlations of PTSD symptom cluster levels and indicators of psychopathology or functional impairment (t-statistics).

Mental health problem attributed to the tsunami Seeing a physician Referral to psychologist or psychiatrist Use of psychotropic medication Sick leave last month General mental health distress (GHQ-28) Sleep disturbances Social withdrawal Feelings of guilt Life satisfaction * ** ***

p < 0.05. p < 0.01. p < 0.001.

Hyper-arousal versus avoidance

Hyper-arousal versus intrusion

Intrusion versus avoidance

8.92*** 3.81*** 4.81*** 4.12*** 4.00*** 10.08*** 9.21*** 6.32*** 7.08*** −5.96***

6.52*** 1.76 1.66 0.57 3.88*** 8.07*** 2.70** 6.71*** 3.92*** −6.50***

3.77*** 2.46* 3.49*** 3.61*** 1.15 3.74*** 6.86*** 1.34 3.98*** −1.20

940


psychopathology and functional impairment, question the PTSD diagnostic criteria in the DSM-IV. Future revisions of the DSM must consider that hyper-arousal symptoms may represent the core of both posttraumatic stress reactions and related functional impairment. Diagnostic criteria may need to be changed to reflect these phenomena so that hyper-arousal symptoms are given more weight. In fact, a PTSD symptom profile that is more consistent with the arousal component of anxiety disorders may better reflect maladjustment to a discrete trauma exposure (Naifeh et al., 2008). Conflict of interest Mr. Heir, Mr. Piatigorsky and Mr. Weisæth report no competing interests. Acknowledgments This study was supported by the Norwegian Directorate of Health and Social Affairs. All authors have had financial support from the Norwegian Centre for Violence and Traumatic Stress Studies. References Breslau, N. (2001). The epidemiology of posttraumatic stress disorder: what is the extent of the problem? Journal of Clinical Psychiatry, 62, 16–22. Breslau, N., Reboussin, B. A., Anthony, J. C., & Storr, C. L. (2005). The structure of posttraumatic stress disorder: latent class analysis in two community samples. Archives of General Psychiatry, 62, 1343–1351. Broman-Fulks, J. J., Ruggiero, K. J., Green, B. A., Kilpatrick, D. G., Danielson, C. K., Resnick, H. S., et al. (2006). Taxometric investigation of PTSD: data from two nationally representative samples. Behavior Therapy, 37, 364–380. Cantril, H. (1965). The pattern of human concerns. New Brunswick, NJ: Rutgers University Press. Catapano, F., Malafronte, R., Lepre, F., Cozzolino, P., Arnone, R., Lorenzo, E., et al. (2001). Psychological consequences of the 1998 landslide in Sarno, Italy: a community study. Acta Psychiatrica Scandinavica, 104, 438–442. Chen, P. Y., & Popovich, P. M. (2002). Correlation: parametric and nonparametric measures. Newbury Park, CA: Sage Publications. Ehlers, A., Mayou, R. A., & Bryant, B. (1998). Psychological predictors of chronic posttraumatic stress disorder after motor vehicle accidents. Journal of Abnormal Psychology, 107, 508–519. Foa, E. B., Riggs, D. S., & Gershuny, B. S. (1995). Arousal, numbing, and intrusion: symptom structure of PTSD following assault. American Journal of Psychiatry, 152, 116–120. Forbes, D., Haslam, N., Williams, B. J., & Creamer, M. (2005). Testing the latent structure of posttraumatic stress disorder: a taxometric study of combat veterans. Journal of Traumatic Stress, 18, 647–656. Goldberg, D. P., & Hillier, V. F. (1979). A scaled version of the General Health Questionnaire. Psychological Medicine, 9, 139–145. Heir, T., Rosendal, S., Bergh-Johannesson, K., Michel, P. O., Mortensen, E. L., Weisæth, L., et al. (2010). Tsunami-affected Scandinavian tourists: disaster exposure and post-traumatic stress symptoms. Nordic Journal of Psychiatry [Posted online 29.04.10]

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